1. Field of the Invention
The present invention relates to a positioning structure, and more particularly to a positioning structure which stacks and fixes a plurality of members to be pierced to a boss that is disposed on, for example, an operation panel of a car stereo.
2. Description of the Related Art
FIG. 1 is a sectional view showing a conventional positioning structure which stacks and fixes a plurality of members to be pierced to a boss that upstands from a main member. For example, this structure may be applied to a case where circuit boards and the like are fixed to an operation panel of a car stereo.
As shown in FIG. 1, a pair of pedestals 201 (only one pedestal is shown) are disposed on the rear face of an operation panel (main member) 200 of a car stereo or the like, and bosses 202 upstand from the pedestals 201, respectively. The bosses 202 are formed into a substantially cross shape as seen in the upstanding direction.
The bosses 202 are required to have a draft angle when they are injection molded integrally with the operation panel 200, and therefore are formed into a shape which is continuously tapered as advancing toward the tip end.
Through holes 204 of a resin housing (first member to be pierced) 203, through holes 206 of a resin member (second member to be pierced) 205, and through holes 208 of a substrate (third member to be pierced) 207 are fitted onto the bosses 202, whereby the resin housing 203, the resin member 205, and the substrate 207 are stacked and fixed to the rear face 200A of the operation panel (main member) 200.
The resin housing 203, the resin member 205, and the substrate 207 comprise the pairs of through holes 204, 206, and 208 to be pierced by the pair of bosses 202, respectively.
In the pairs of through holes 204 and 204, 206 and 206, and 208 and 208, the through holes 204, 206, and 208 on one side are formed into a circular shape of the same size, and the other through holes 204, 206, and 208 are formed into an elliptic shape of the same size. Since the other through holes 204, 206, and 208 are formed into an elliptic shape, it is possible to absorb a production error.
The pair of bosses 202 are formed into a tapered shape in order to ensure a draft angle, and the through holes 204, 206, and 208 are formed to be identical with each other in size and shape. When the through holes 204 of the resin housing 203, the through holes 206 of the resin member 205, and the through holes 208 of the substrate 207 are fitted onto the bosses, therefore, the gaps between the bosses 202 and the through holes 204, 206, and 208 are larger as the members are placed in a higher level.
Specifically, the fitting between one of the bosses 202 and one of the through holes 206 of the resin member 205 is looser than that between the boss 202 and one of the through holes 204 of the resin housing 203, and the fitting between the boss 202 and one of the through holes 208 of the substrate 207 is looser than that between the boss 202 and the through hole 206 of the resin member 205.
Consequently, the resin member 205 and the substrate 207 are moved along the surface direction in the directions of the arrows with respect to the operation panel (main member) 200 and the resin housing 203, so that an error may be caused in an assembling process, thereby causing the possibility that, for example, a switch failure occurs.
Since the resin housing 203, the resin member 205, and the substrate 207 are simply stacked, there is the possibility that the soft resin member 205 is crushed in the thickness direction by the resin housing 203 and the substrate 207 and its function is impaired.